Numerical simulation of buoyancy-driven turbulent ventilation in attic space under winter conditions

Shimin Wang, Zhigang Shen, Linxia Gu

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Attic design and construction have significant impacts on residential buildings' energy performance. In order to understand how passive ventilation rates affect ridge-vent attic's performance, a two-dimensional steady-state finite volume model is employed to simulate the buoyancy-driven turbulent ventilation and heat transfer in a triangular attic space of a gable-roof residential building under winter conditions. The modeled attic has a pitch of 5/12 and a passive ventilation system, consisting of continuous ridge and soffit vents. The v2f model is used to analyze the turbulent air flow and natural convection heat transfer inside the attic. The effects of ambient air temperature, vent size, and ceiling insulation on heating load and ice dam formation are investigated. The thermal performance of the vented attic is compared with a sealed attic as well. The simulation results reveal that symmetrical air flow patterns exist in a vented attic, in contrast to the asymmetrical air flow patterns found in a sealed attic. In addition, it is suggested that increasing vent size results in higher ventilation air flow rate but barely affects the attic heating load, and that both sufficient ventilation and insulation are needed to ensure the proper functions of the attic and its energy efficiency.

Original languageEnglish (US)
Pages (from-to)360-368
Number of pages9
JournalEnergy and Buildings
Volume47
DOIs
Publication statusPublished - Apr 1 2012

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Keywords

  • Attic
  • CFD
  • Heating load
  • Ice dam
  • Insulation
  • Turbulence
  • Ventilation

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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